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Re: FourierTransform of Sign^2 ?

• To: mathgroup at smc.vnet.net
• Subject: [mg80045] Re: [mg79997] FourierTransform of Sign^2 ?
• From: "Jung-Tsung Shen" <jushen at gmail.com>
• Date: Sat, 11 Aug 2007 02:11:10 -0400 (EDT)
• References: <200708100552.BAA10934@smc.vnet.net>

Thanks for checking this. I found a version of  5.1 and it gives the
correct answer. I guess it's a bug in v. 5.0 then.

JT

On 8/10/07, Sseziwa Mukasa <mukasa at jeol.com> wrote:
>
> On Aug 10, 2007, at 1:52 AM, Jung-Tsung Shen wrote:
>
> > I tried to evaluate the following Fourier Transform:
> >
> > FourierTransform[Sign[y] Sign[y], y, q]
> >
> > where Sign is the sign function. Instead of Sqrt[2 Pi]*DiracDelta[q],
> > Mathematica (v. 5.0, Mac) gives
> >
> > -Sqrt[2 Pi]*DiracDelta[q]
> >
> > with a minus sign. Is this a bug or I am doing something wrong here?
>
> v5.2 on a Mac gives
>
> In[1]:=
> FourierTransform[Sign[y] Sign[y], y, q]
> Out[1]=
> Sqrt[2 Pi] DiracDelta[q]
>
> Regards,
>
> Ssezi
>

• References:
  • FourierTransform of Sign^2 ?
    • From: "Jung-Tsung Shen" <jushen@gmail.com>